Lovely job with the colors. Your line art is as cute as always. I think a black (Sabbath) T-shirt or a red T-shirt like the one the Armored Adventures Tony wears might have suited little Tony here a bit better, but this rendition with the arc reactor glow visible is lovely too. ^_^

Say, have you ever considered drawing a kid Science Bros pic with little Bruce and little Tony together? Or maybe a scenario with kid Tony and adult Bruce since you did one with kid Bruce in that one Flash vid?